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Cladribine Side Effects

The most commonly reported side effects of cladribine include fatigue, headache, and lymphocyte count decreased, based on 9,175 FDA adverse event reports from 2004 to 2025. 3.0% of reports found the drug to be ineffective.

Cladribine side effects

Percentages show how often each reaction appears relative to total reports for cladribine.

1
Fatigue8.4%768
2
Headache6.9%631
3
Lymphocyte Count Decreased5.0%461
4
Multiple Sclerosis Relapse4.9%452
5
Nausea4.3%395
6
Pneumonia4.0%369
7
White Blood Cell Count Decreased3.6%332
8
Off Label Use3.6%326
9
Drug Ineffective3.0%273
10
Urinary Tract Infection2.9%266
11
Pyrexia2.9%262
12
Multiple Sclerosis2.6%238
13
Asthenia2.4%221
14
Lymphopenia2.3%215
15
Febrile Neutropenia2.1%197

These are voluntary reports and do not establish that cladribine caused these reactions.

Report severity

75.7%Serious6,942 reports
23.7%Hospitalizations2,174 reports
8.4%Fatal768 reports

Seriousness is determined by the reporter, not by OpenClaim.

Cladribine drug interactions

Other drugs that appear in adverse event reports alongside cladribine. Drugs flagged as a suspected cause appear in the first column. Drugs taken at the same time but not suspected appear in the second.

Also suspected

1
Cytarabine7.3%674
2
Rituximab5.1%467
3
Cyclophosphamide3.6%332
4
Mitoxantrone-hydrochloride2.9%266
5
Filgrastim2.1%197
6
Etoposide2.0%186
7
Idarubicin-hydrochloride1.9%172
8
Prednisone1.7%154
9
Vincristine-sulfate1.6%149
10
Methotrexate1.6%143
11
Venetoclax1.4%128
12
Fludarabine-phosphate1.4%125
13
Prednisolone1.3%119
14
Dexamethasone1.3%117
15
Doxorubicin-hydrochloride1.3%116

Taken alongside

1
Cytarabine2.2%203
2
Ergocalciferol1.9%172
3
Acyclovir1.8%163
4
Acetaminophen1.4%130
5
Baclofen1.3%121
6
Sulfamethoxazole1.1%103
7
Mitoxantrone-hydrochloride1.1%100
8
Cholecalciferol1.0%96
9
Filgrastim1.0%95
10
Allopurinol1.0%92
11
Aspirin1.0%91
12
Cyclophosphamide1.0%88
13
Gabapentin1.0%88
14
Levothyroxine-sodium0.9%86
15
Trimethoprim0.9%84

Co-occurrence in adverse event reports does not establish a drug interaction. Patients often take multiple medications, and these lists reflect prescribing patterns rather than causal relationships. Consult a healthcare provider about potential drug interactions.

Who reports cladribine side effects

62.6% of cladribine adverse event reports involve female patients and 29.0% involve male patients. The largest age group is adult at 83%. These figures reflect who reports side effects, not underlying risk.

Sex

Female62.6%
Male29.0%
Unknown8.3%

Age group

< 21.5%
2–111.2%
12–170.6%
18–6482.8%
65+13.9%

What is cladribine used for

Conditions and purposes for which patients were taking cladribine when the adverse event was reported.

Acquired HaemophiliaAcute LeukaemiaAcute Lymphocytic LeukaemiaAcute Monocytic LeukaemiaAcute Myeloid LeukaemiaAcute Myeloid Leukaemia RecurrentAcute Myeloid Leukaemia RefractoryAcute Promyelocytic LeukaemiaAngioimmunoblastic T-cell LymphomaAnti Factor Viii Antibody IncreasedAstrocytomaAcquired HaemophiliaAcute Disseminated EncephalomyelitisAcute Erythroid LeukaemiaAcute Febrile Neutrophilic Dermatosis

Showing 15 of 241 indications

Cladribine brand names and reporting trend

Cladribine is sold under the brand name Mavenclad.

Brand names

Mavenclad3,136

Quarterly reports (20042025)

20052010201520202025

An upward trend reflects increased FAERS reporting overall, not necessarily increased risk.

Taking cladribine with another medication?

Ask OpenClaim about your specific drug combination. Get a sourced report using FDA data, drug labels, and medical literature.